Coal-stove



3 Sheets-Sheet 1. SHIELDS & PIERCE.

Heating Stove.

Patented Jany 7, 1851.-

3 Sheets-Sheet 2.

SHIELDS 6L PIERCE.

Heating Stove.

Patented Jany .7, 1851.

x emph", wumman. D. (L

SHIELDS & PIERCE.

^ 3 Sheets-Sheet 3.

Heating Stove.

Patented Jany 7, 1851.

Nox 7,891.

UNITED STATES ATENT OFFTCE.

JAMES SHIELDS, OF NEW YORK, AND SAML. PIERCE, OF TROY, NEW YORK.

COAL-STOVE.

Specification of Letters Patent No. 7,891, dated January 7, 1851.

To all whom t may concern Be it known that we, JAMES SHIELDS, of thecity, county, and State of New York, and SAMUEL PIERCE, of Troy, in thecounty of Rensselaer and State of New York, have invented a new anduseful Improvement in Stoves for Burning. Anthracite and BituminousCoal, and that the following is a full, clear, and exact description o-fthe principle or character which distinguishes my invention from allother things before known and of the method of making, constructing, andusing the same, reference being had to the accompanying drawings, makingpart of this specification, in which- Figure l, is a plan of ourimproved stove for burning anthracite coal with the top removed, andFigs. 2 and 3, vertical sections of the same taken at the lines A, a,and B, of Fig. l, and Figs. t, 5 and 6 are like views and sections of astove on the same principle adapted to the burning of bituminous coal.

The same letters indicate like parts in all the figures.

Our invention is of an improvement on the downward draft stove inventedby Dr. Eliphalet Nott, in which the charge of coal is contained in afire chamber extending above the aperture for the draft leading to theflues through which the products of combustion circulate, to heata largeamount -of metal surface for the radiation of heat.

We have ascertained by careful investigation that the gaseous productsof combustion in this stove are inflammable when anthracite coal (theonly fuel heretofore used in this kind of stove) is burned; theproportion of inflammable gases being greatly increased when bituminouscoal is substituted. These inflammable gases escaping unconsumed, giveout, comparatively, but little heat, and from this circumstance a stovewhich in other particulars presents un-V questionable advantages overothers has been in a greatmeasure superseded. In other stoves, or suchas have what is called the upward draft the whole charge of coal soonreaches the incandescent state, the draft being carried directly throughthe whole charge, from which it follows as a necessary consequenceeither that such a stove will give out too much heat with acorresponding consumption of fuel, or the charge of coal will be toosmall, requiring the charge to be frequently renewed, which is attendedwith much annoyance and labor and with a great waste of fuel, as it iswell known that coal, particularly anthracite, burns better and withgreater economy in large masses. But in Notts downward draft stove, theheated draft, that is, the gases evolved from the coals in'anincandescent state, do not pass through the whole charge but passdirectly through that portion of the charge which'isbelow the throat ordraft aperture, the other portion of the charge above the throat simplyundergoinga dist-illing or preparatory process; and

therefore all that part of the fire-chamber above lthe throat may becalled a chamber of preparation.

To effectually consume the inflammable gases evolved by an imperfectcombustion, such as usually takes place in stoves, these gases should bein .a highly-heated state when they meet and mingle with the supporterof combustion, and the higher the temperature, the more perfect will bethe combustion; but in all the upward draft stoves, the gases evolved bythe incandescent coals in passing up through the upper part of thecharge, necessarily lose a great portion of their heat, and become toomuch cooled to be inflamed advantageously; and in the commencement ofthe burning of a charge the distilling process is carried on with greatrapidity, giving out a greater quantity of inflammable gases than can beconsumed, and in a short time the whole charge becomes incandescent, andthen the quantity of inflammable gases given out is too small to need tobe consumed. Hence, in such stoves, if means be employed for consumingthe inflammable gases, at first such means will be insufficient, and ina short time comparatively useless, and, what is more objectionable, inthel commencement of a charge the inflammable gases given out by t-heincandescent coals, become so much cooled that they can only be consumedby means of highly-heated atmospheric air; and from this it follows thatafter the whole charge becomes incandescent, and the quantity ofinflammable gases given out is very small, the means employed forheating the supply of atmospheric air becomes a waste. But in thedownward draft stove, such as we have above indicated, the upper part ofthe charge in the chamber of preparation is kall the time exposed tonearly the same heat from the incandescent coals below the draft throatand the inflammable gases given out with a nearly regular supply mustpass through a portion of the incandescent coals to reach the draftthroat', and in so doing they become highly heated and thus reach arstate in which they can be inflamed by admixture even with coldatmospheric air.

lVith these preliminary remarks we declare that the principle orcharacter of our invention which distinguishes it from all other thingsbefore known, consists in combining with a fire chamber, having thedraft throat leading to the flue or flues, below the top of the chargeof coal, the necessary means for supplying a current or currents ofatmospheric air at or near the said throat, for the purpose of inflamingthe combustible gases given out by the charge of coal, by means of whichcombination we are enabled effectually to iniame the combustible' gasesevolved, while at the same time we are enabled to put a heavy charge ofcoal in the stove, and to give out the combustible gases more regularlyand at a higher temperature than in any other stove known to us.

In the accompanying drawings (a) represents the fire chamber with agrate The front of the lire chamber is provided with two sets of doorsl(c, c) and (d, d), the set (c, c) above the grate, and the other (d, d)in front of the grate. Below the grate there is the usual sliding ashpan (e) which, when closed, excludes air. The top of the fire-chamber iscovered wit-h a plate (f) which extends to the back-plate- (g), and overthe tire chamber this plate is provided with draft holes leading to theexit pipe (h.) which holes are governed by a sliding damper so that whenthis sliding damper and ash pan are opened, there is a direct draft asin ordinary stoves for starting the fire; but after this the damper mustbe closed as also vthe ash pan. The fire-back, or back of the firechamber, which should be made of fire brick or some other refractorysubstance, is in twoparts (j, 7c), the upper part (j) extending downfrom the top plate to some distance below the top of the grate, that aportion of the chargeof coal may be above its lower edge, and the otherpart (Ze) atsome distance back of it leaving a throat (Z) between thetwo, through which the products of combustion pass to the main flue orchamber of inflammation between the part (j) of the fire-back and thestove-back (m). And the space between the lower part (7c) of thelire-back and the stove-back constitutes a chamber into whichatmospheric air is admit-ted from the room through apertures governed bya damper or dampers rI he top of this air chamber is covered by aninclined plate (o) perforated with small holes through which atmosphericair passes in small jets to mingle with and inflame the highly heatedcombustible gases as they pass from the lire chamber throughfthe throatto the chamber of inflammation. The top of this chamber of inflammationbeing covered, the products of this iinal combustion pass out throughlateral apertures (p, p) into descending flues (g, g) at the sides;thence, under the lower edge of two vertical partitions (r, 7g) up twoside vertical flues (s, 8,) in front of the iues (Q, QQ and then to thespace (t) between the top-plate of the firelibzmber and the top to theeXit pipe After the tire has been kindled the draft is admitted throughthe front upper doors, and, unless a very rapid combustion be required,the air that passes through the imperfect joints ofthe doors will besuflicient. The draft passes through the charge of coal above carryingthe infiammable gases down to, and through a portion of the incandescentcoals to the throat, through which they pass with the gases evolved fromthe combustion of the' incandescent coals, the gases thus becoming sohighly heated as to inlame the moment they meetwith the jets ofatmospheric air from the air chamber, and thus produce a great body offlame in the chamber of inflammation, which thence passes through theHues, heating to a high temperature all the parts of the stove throughwhich the vlues pass.

Vhen our improved stove is applied to the burning of bituminous coal, weprefer to leave the grate closed at the bottom as represented in F ig.4i, and the chamber of inflammation narrowed toward the top, as at (v)to make a second throat on the principle secured by Letters Patentgranted to James Shields and James Cole, bearing date the 10th day ofMarch A. D. 1849. On this second throat we place an inverted funnel (fw)through which the products of combustion pass into a drum (m) in whichthe products of combustion circulate, and then pass out throughapertures (y, y,) in the bottom of the said drum or top-plate of thefire chamber, and thence through the fiues to the exit-pipe in the samemanner as in the stove for burning anthracite coal above described.

vWe have described such arrangements of lues &c. yas we have essayedwith success in the application of the principle of our invention, butWe do not Wish to limit ourselves to these, as they may be variouslymodified. But

What We claim as our invention and desire to secure by Letters Pat-entis- The method substantially as herein described of supplying currentsof atmospheric air to the products of the combustion at or near thethroat leading from the rechamber to the flues, in combination with whatis known as Notts fire-chamber, having the draft throat leadingtherefrom between t-he top and the grate that the upper

